With sweltering heat descending on several countries around the world, and the Fondation Abbé Pierre's latest study "Summer energy precarity: a new form of poor housing" reminding us of the inescapable link between energy precarity and heat peaks, it is becoming increasingly clear that urban overheating is a public health issue.
Worse still, it is a matter of survival, according to a study in "The Lancet Planetary Health", which found that Paris is the deadliest city in Europe in the event of a heatwave.
A C40 Cities study recently highlighted the fact that extreme heat is the second greatest climate-related risk, after food-related risks. It is estimated that it affects 1.6 billion people worldwide, and that 1 in 7 French people will be exposed to an increasing number of abnormally hot days and nights over the next few decades.
The lack of vegetation and the choice of climatic materials are contributing to the proliferation of what are known as urban heat islands (UHIs), with harmful consequences for health and even mortality, according to data from the French Institute for Health Monitoring.
Faced with this situation, there are solutions to make cities and their infrastructures more resilient. Town and country planners have a role to play, and so does Egis.
The question of how to adapt housing to the climate and heat has been on the agenda of our Group for several years, and has been incorporated into our design studies, but it's particularly since the heatwave of 2003 that the subject has come to the forefront of public opinion.
On the scale of a district or a building, there are various solutions to be adopted, such as planting vegetation (when experienced, this process can produce temperature differences of more than ten degrees, according to specialists), reorganising spaces or using cooling materials.
It also appears that modelling tools have a decisive role to play in assisting decision-making.
ICEtool was developed with this in mind, based on a database of materials and their physical and technical characteristics. Thanks to this open-source, multi-criteria assessment tool, which is accessible to all, towns and cities can model sustainable and resilient public developments for their area. In concrete terms, they can quickly, scientifically and visually visualise the phenomenon of heat islands and the means of countering them and bringing down the temperature.
By entering data such as the height of a building or the type of pavement, they can find out the temperature in their neighbourhoods over the course of a day and measure the impact of changes such as planting vegetation or changing the pavement.
Applied to the CartoRhin brownfield redevelopment project in Alsace, ICEtool was used to achieve clear planning objectives: to make the district more resilient to climatic and natural hazards. In this case, ICEtool was used to model the impact of the development on the heat island effect, depending on a number of parameters. Several scenarios were compared, then the selected one was compared with the initial state to assess the improvement generated.
This work has been recognised, as Egis, represented by its project manager William Weltzer, was awarded the "Mention - Grand Prix Rénovation Urbaine" at the Construction21 Green Solutions Awards on 4 July.
At Egis, we are convinced that it is by multiplying these decision-making tools that cities will be able to take sustainable action on their territories and infrastructures. In fact, this is one of the five commitments Egis has made in the face of the climate challenge, as part of its Impact the Future corporate project.
